[PATCH 1/2] msvcrt: Back up and restore the FPU state in setjmp/longjmp on arm

[Martin Storsjö]

On Fri, 8 Sep 2017, Alexandre Julliard wrote:

> Martin Storsjo <martin at martin.st> writes:
>
>> Signed-off-by: Martin Storsjo <martin at martin.st>
>> ---
>>  dlls/msvcrt/except_arm.c | 22 ++++++++++++++++++++--
>>  1 file changed, 20 insertions(+), 2 deletions(-)
>
> This doesn't build here with the Android NDK:
>
> arm-linux-androideabi-gcc -c -o except_arm.o ../../../wine/dlls/msvcrt/except_arm.c -I. -I../../../wine/dlls/msvcrt \
>  -I../../include -I../../../wine/include -D__WINESRC__ -D_MT -D_MSVCR_VER=0 -D_REENTRANT -fPIC \
>  -Wall -pipe -fno-strict-aliasing -Wdeclaration-after-statement -Wempty-body -Wignored-qualifiers \
>  -Wstrict-prototypes -Wtype-limits -Wunused-but-set-parameter -Wvla -Wwrite-strings -Wpointer-arith \
>  -Wlogical-op -gdwarf-2 -gstrict-dwarf -g -O2 -fno-diagnostics-show-caret -D__ANDROID_API__=26 -marm
> {standard input}: Assembler messages:
> {standard input}:44: Error: selected processor does not support ARM mode `vmrs r2,fpscr'

Ok, that explains why this was left out so far.

Perhaps this should go within some ifdef, if I could just figure out the 
right one. When testing with the NDK gcc, I seem to be able to assemble 
this kind of instructions once I add -mfloat-abi=softfp, and when checking 
the defines, the main difference seems to be that the __SOFTFP__ define 
disappears. So within #ifndef __SOFTFP__, your build would still work.

FWIW, such a build without support for the VFP registers isn't ABI 
compatible with modern armv7 windows, since modern armv7 windows is 
hardfloat (passes float arguments in FPU registers). But I guess it's 
useful as a winelib build anyway.

// Martin